winter model output Winter Model Output Discussion -12Z 07/02/13 onwards

[ChartViewer]

One of the best things from this winter has been watching the output unfold and the learning we have gained. The tech thread is and has been superb as has commentary from many on here. I understand frustration that many have felt and continue to feel but we live in the uk and the sledge has been out once and for Bouremouth that is a big tick in the box.

Anyway the big southward correction of the impending low has not been modelled yet!!!!

And the best day ive seen was your title..it went downhill after that haha

[MKN]

But for all the rebuttle, the science, the 'high level' thoughts its been a plain jane winter with no greenland blocking.

In your back yard I presume your referring to there? We had snow on the ground during January for 14days straight with a maximum depth of just over 8" level snow. The most apparently since 91 for here although I barely remember that year personally. All in all the snowiest here for a long long time. Not as cold as 2010 but we only managed 6/7cms at the best point and that was 5 days before the lot melted.

[Gibby]

Good evening. Here is the report on the 12z outputs from GFS, UKMO and ECM for tonight Friday February 8th 2013.

All models seem to be in virtual agreement on the sequence of events over the next 4-5 days despite different nuances in the atmosphere creating very difficult to predict with accuracy events in any one particular place or area. The next 24 hours sees a front moving slowly East into Central areas over the coming 12-24 hours. Any remaining wintry showers in the SE should move away tonight with some clear spells leading to cold and frosty conditions to develop. as the front moves in to the spine of Britain overnight outbreaks of rain will gradually intensify with some of the heavier bursts turning to sleet or wet snow with slight accumulation possible here and there. The far West will be less cold and rather cloudy but largely dry. By Sunday a new and vigorous trough is shown to move in from the West forming Low pressure over Southern Britain through the day. Heavy rain will affect all Southern and Western areas from very early in the day turning to snow as it reaches areas North and East of roughly London to Birmingham. Clearer showery air may reach the SW late in the day with a strong NW wind. By Monday the Low complex with centres near the English Channel and NW Ireland weaken and collapse SE with rain and snow dying out though leaving a legacy of wintry showers in the East under a cold East or NE flow over the period up to the middle of the week.

GFS then shows further disrupting Low pressure sliding SE in the second half of next week with further spells of cold rain and sleet and snow for more Northern and Eastern areas. The pressure pattern becomes more Atlantic based for a time then as Low pressure drifts East to the North with rain and showers for all. Later in FI High pressure is shown to re-develop over Scandinavia with the Jet Stream over the Atlantic more favourably positioned to ensure most of the UK come under a more definitive spell of cold and potentially wintry weather though as shown temperatures are higher than should be with such good synoptics.

The GFS Ensembles show an unsettled couple of weeks with temperatures at 850 levels close to the average for mid February. in the North the operational was a cold outlier towards the end of the run while at times in the South it was slightly above the mean for both the run and the long term mean.

The Jet Stream shows the arcing of the flow high over the UK and its passage South over the UK breaking down over the coming 48 hours. It then realigns to a latitude of around 50-55deg N over the Atlantic before turning SE to the SW of Britain and on down to Southern Europe where the Eastward track of the flow continues unabated.

UKMO for midday on Thursday shows Low pressure near the Faroe Islands with a milder SW flow over the UK with rain at times, especially in the North and West.

ECM shows a similar pattern to this morning with a much more pronounced domination of High pressure from Scandinavia extending a ridge towards Southern Britain. Later in the week High pressure loses grip to the NE setting up shop closer to the UK. The Jet flow then is shown to ride over the top of the High and the inevitable sinking of the system commences by Day 10. Throughout this spell the weather over the UK ould stay cold and bright with frost at night and generally dry.

In Summary the weather looks like staying on the cold side for the time being. The events of later this weekend and start of next week looks like being firmed upon now with the snow risk transferred to more Northern and Eastern areas before things steadily dry up and settle down towards the middle of next week with cold bright days and frosts by night. Longer term things look like turning quickly milder after midweek from UKMO and to some extent GFS too while ECM maintains an ambience of cold and settled conditions almost to the end of it's run, especially in the South.

[nick sussex]

GWO phase plots are in the tech thread now courtesy of Recretos. Almost half the ECM suite clustered around decent Easterly solutions on the 12z ECM yesterday, will be interesting to see just how diluted they are tonight.

With the operational going wild for mild toward the end of the run, perhaps this time it is all outlier / earlier tonight.

Trough disruption is just precarious for predicting patterns, it seems combined with the lessening net jet energy that each run brings different dissipation and angling of lows.

Will be good to see Stewarts take on the analogs here..

Hope you are all recovered Nick, some shortwaves were asking after you in your convalescence.

Thanks Lorenzo, getting there slowly. I was hoping to see some output that might shock me out of my current fuzzy state but sadly the ECM although coldish doesn't really do much!

Looking at where the PV is its hard to make a case for anything interesting unless its from the east or ne and even then we do need to see a decent cold pool which at least the 00hrs ECM hinted at, tonights has backtracked from that.

Still a few weeks to go so lets hope for a change.

[SMU]

In your back yard I presume your referring to there? We had snow on the ground during January for 14days straight with a maximum depth of just over 8" level snow. The most apparently since 91 for here although I barely remember that year personally. All in all the snowiest here for a long long time. Not as cold as 2010 but we only managed 6/7cms at the best point and that was 5 days before the lot melted.

Without wishing to go off topic. check out the MEt office website for Average days of snow falling & lying- your stats are just over average- but condensed into one short period.thus far out whats 9 weeks of 12, those 2 Jan weeks will certainly mask over the poor winter for many- but at least something is better than nothing....

[Jeremy Shockey]

thanks Gibby , a brilliant and balanced summary as ever

[Frosty.]

One of the best things from this winter has been watching the output unfold and the learning we have gained. The tech thread is and has been superb as has commentary from many on here. I understand frustration that many have felt and continue to feel but we live in the uk and the sledge has been out once and for Bouremouth that is a big tick in the box.

Anyway the big southward correction of the impending low has not been modelled yet!!!!

Do we know for sure that there will be a big southward correction of the low or is that just what everyone in southern england is hoping for?

even a southward correction won't make much difference to the northeast, they should still get plenty of snow showers as that very cold easterly sets in until tues/wed.

[joggs]

Yeh thats what i find interesting is that people keep saying southward trend is expected etc but the meto n bbc show northern n central areas with 4" fairly wildly!.Just because its happened before means diddly squat and the meto with their super comps etc are surely on the money within 24/48 hrs.I think people are just hoping these southward movements come to fruition imho.

[MrSunshine]

Yes I agree top post Gibby as always!

[ChartViewer]

CMA T96 not too shabby

[ANYWEATHER]

Without wishing to go off topic. check out the MEt office website for Average days of snow falling & lying- your stats are just over average- but condensed into one short period.thus far out whats 9 weeks of 12, those 2 Jan weeks will certainly mask over the poor winter for many- but at least something is better than nothing....

Pointless moaning about lying snow etc. what about the late eighties right through the nineties and early to mid naughties. Little snow during that time for [MANY] But not all. Winters in the Uk are seemingly coming back, despite what is in your Backyard. Met Office stats etc......

Edited February 8, 2013 by ANYWEATHER

[Ian Brown]

Yeh thats what i find interesting is that people keep saying southward trend is expected etc but the meto n bbc show northern n central areas with 4" fairly wildly!.Just because its happened before means diddly squat and the meto with their super comps etc are surely on the money within 24/48 hrs.I think people are just hoping these southward movements come to fruition imho.

Joggs, often in this situation low pressures like this trend further South or stay to the West - however here we do not have HP close to the North or close to the East - the wedge of 552 is to the West of Northern Norway, so there is no reason why there should be any trending South of Sundays LP.

Anyway, the ECM looks wrong tonight because at T120 I would expect the Low pressure to dive SE in the same way that the GFS shows, splitting the AH and the Scandi High but it doesnt and if that's not right then the rest of the ECM is wrong.

[Weather-history]

But for all the rebuttle, the science, the 'high level' thoughts its been a plain jane winter with no greenland blocking

I actually disagree with this. I think it hasn't been plain Jane winter but a complex winter at times, synoptically. The last 4 weeks have been a nightmare to work out, it really has been complex, one of the most complex winters for years. A lot of winters are easy to work out synoptically, zonal, blocking with fine tuning for greater detail. For this winter, it hasn't been the case. It has made model watching frustrating at times but it hasn't been boring. Yet again another complicated set-up for this weekend.

[Ian Brown]

Pointless moaning about lying snow etc. what about the late eighties right through the nineties and early to mid naughties. Little snow during that time for [MANY] But not all. Winters in the Uk are seemingly coming back, despite what is in your Backyard. Met Office stats etc......

Glad I don't live in an area that is so dependent on one type of set-up...

[ChartViewer]

I actually disagree with this. I think it hasn't been plain Jane winter but a complex winter at times, synoptically. The last 4 weeks have been a nightmare to work out, it really has been complex, one of the most complex winters for years. A lot of winters are easy to work out synoptically, zonal, blocking with fine tuning for greater detail. For this winter, it hasn't been the case. It has made model watching frustrating at times but it hasn't been boring. Yet again another complicated set-up for this weekend.

For me the model drama has outweighed the actual weather that has been delivered if im very honest

Edited February 8, 2013 by ChartViewer

[cooling climate]

Unless there is a marked shift in synoptics IE the trough disrupting from the west/northwest

and the cold uppers being kept away to the north and east by what looks like a secondary

low running northwest from the continent then for many this may not amount to more than

a tin a beans.

The GFS run which is not to disimilar to the ECM has temperatures over much of England

on Sunday of 3-4c and Monday 4-6c which does not support laying snow or falling snow for

that matter.

Lets hope the UKMO is the more accurate of the model runs this evening as it is a colder run

than the other two and much more conducive for snow.

[Ian Brown]

I actually disagree with this. I think it hasn't been plain Jane winter but a complex winter at times, synoptically. The last 4 weeks have been a nightmare to work out, it really has been complex, one of the most complex winters for years. A lot of winters are easy to work out synoptically, zonal, blocking with fine tuning for greater detail. For this winter, it hasn't been the case. It has made model watching frustrating at times but it hasn't been boring. Yet again another complicated set-up for this weekend.

Yes, apart from the (largely) zonal December it has not been anything like any of the winters since we have all been doing this on the internet.

[R.P. McMurphy]

JMA for t60, his time-frame seems to be the one to watch tonight if you live in the more southern half of the UK.

Not sure I follow? It's quite pathetic for the South really with slush / sleet for many. I expect the Saturday runs to fall in line with a Northwards correction.

[Froze were the Days]

eeeerrr! just seen the back end of the ECM and that doesn't look good also looked at the latest FAX charts and have to say I'm underwhelmed of what's on offer considering the consistent projections of a supposed 'slider' from the Euro's and what have we got?...well we don't have a slider, with the 'true' in a sense continental air well to the north east and the current pattern becoming all too cyclonic (over the next few days). Don't get me wrong certain central areas of the UK could see a good dumping but as a poster mentioned a while back we are chasing and continue to chase real winter synoptics.

So far this winter has offered plenty of opportunities and has to be said a good model watching winter bar the pre-Xmas and New Year write-off period but as Mr Murr stated could turn out to be a pretty basic winter with just a slightly colder than normal anomaly.

Oh by the way where's the famed Greenland High gone? which we saw so much off last April into the early summer.

Edited February 8, 2013 by Froze were the Days

[Frosty.]

Anyway, the ECM looks wrong tonight because at T120 I would expect the Low pressure to dive SE in the same way that the GFS shows, splitting the AH and the Scandi High but it doesnt and if that's not right then the rest of the ECM is wrong.

Yes but that is not what the metoffice update mentioned for next week, their update did not suggest any slider lows or undercut after this weekends episode, if anything, what the ecm 12z is showing is more in line with latest metoffice thoughts.

[Long haul to mild]

Unless there is a marked shift in synoptics IE the trough disrupting from the west/northwest

and the cold uppers being kept away to the north and east by what looks like a secondary

low running northwest from the continent then for many this may not amount to more than

a tin a beans.

The GFS run which is not to disimilar to the ECM has temperatures over much of England

on Sunday of 3-4c and Monday 4-6c which does not support laying snow or falling snow for

that matter.

Lets hope the UKMO is the more accurate of the model runs this evening as it is a colder run

than the other two and much more conducive for snow.

I always follow the UKMO and FAX charts at this range as they are usually more accurate, so I think the interest for this weekend and early next week is not over yet.

I generally use ECM for mid term trends and I don't really use the GFS at all at the moment to be honest, because its been awful this winter!

[Roger J Smith]

The glass half full position would be that you could get to something very wintry across the south (north seems already assured) without changing pattern or large-scale features, just tweaking details on models. Probably each model has ensemble members that could support snow but this at the moment is the minority position for southern England. I think there could be a somewhat different outcome once this slider actually starts to slide. It would not be the first time that a system not yet in existence turned out to be 100-200 miles off the consensus track or (related) that the thickness pattern was one interval (6 dam) off. The ripple effects of explosive cyclogenesis on the other side of the Ocean may become apparent in future model runs.

Lots of things to hold our interest even if the prospects seem a bit dull for some. Meso-scale but retrograde system over eastern Baltic could factor into the outcome also. Holland ought to like the results (as I'm sure we will hear).

[MrSunshine]

Not sure I follow? It's quite pathetic for the South really with slush / sleet for many. I expect the Saturday runs to fall in line with a Northwards correction.

Looks like a slush fest to me only -4 uppers in the south of England, not sure what the Dew points are progged to be though.

[Sawel]

Check out how well the ECM has been verifying at +120 hrs this past 7 days...

http://www.emc.ncep..../html/acz5.html

Edited February 8, 2013 by Sawel

[ANYWEATHER]

The glass half full position would be that you could get to something very wintry across the south (north seems already assured) without changing pattern or large-scale features, just tweaking details on models. Probably each model has ensemble members that could support snow but this at the moment is the minority position for southern England. I think there could be a somewhat different outcome once this slider actually starts to slide. It would not be the first time that a system not yet in existence turned out to be 100-200 miles off the consensus track or (related) that the thickness pattern was one interval (6 dam) off. The ripple effects of explosive cyclogenesis on the other side of the Ocean may become apparent in future model runs.

Lots of things to hold our interest even if the prospects seem a bit dull for some. Meso-scale but retrograde system over eastern Baltic could factor into the outcome also. Holland ought to like the results (as I'm sure we will hear).

A "BIG"turnaround in your forecast the other day! But with lots of respect, this is one difficult forecast.....AW.